Massage stone



FIG. 1 is an elevated isometric view of a massage stone;

FIG. 2 is a view representing both front and rear views thereof, said front and rear views being identical;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top side view thereof; and,

FIG. 6 is a bottom side view thereof. 

CLAIM The ornamental design for a massage stone, as shown and described. 